The invention relates to a method for synthesizing
albendazole. The method comprises the following steps of: (a) adding
carbendazim,
sodium sulfocyanate and glacial
acetic acid to a reactor, dropwise adding 28%
hydrogen peroxide while controlling the temperature to be 25-40 DEG C, carrying out heat preservation and reaction for 4-6 hours after the dropwise adding process is completed, and obtaining thiocyanide after glacial
acetic acid is recovered through negative-pressure
distillation; and (b) adding 20% aqueous
potassium hydroxide solution to the thiocyanide while adding benzyltriethylammonium
chloride, then dropwise adding 1-bromopropane, and reacting for 4-8 hours while controlling the temperature to be 45-60 DEG C, thereby obtaining the
albendazole. According to the method, the potential safety
hazard caused by the fact that a highly toxic substance, namely
chlorine gas, is used for preparing
albendazole is avoided successfully, and the influence on the quality and yield of the product, caused by side reactions resulting from the adoption of the
chlorine gas, is eliminated successfully, so that the quality and yield of an intermediate are improved greatly; meanwhile, the adoption of alkali
sulfide is cancelled, and then, the environmental
pollution caused by a byproduct, namely
thioether, produced due to excessive alkali
sulfide is avoided, so that the method is perfectly suitable for industrial production; and furthermore, all the raw materials are low in cost and are purchased easily, and the operation is safe.